Power Kite Forum

Depower - "Sheeting" Terminology

kiteNH - 20-5-2008 at 01:46 PM

Can someone help me understand sheeting terminology?

When someone writes that they sheeted the kite in, does this mean pulling the bar in? Sheeting out means putting the bar out?

Also (and I might be going off topic on my own post here) does this terminology apply to depower foils (like my Access) and not just LEI's? I don't think that I've figured out how to fly depower very well so it would help to at least understand what people say/write about flying them. :puzzled:

B-Roc - 20-5-2008 at 01:59 PM

I don't fly depower but I have in the past and as I understand it, sheeting out is letting the bar out and sheeting in is pulling the bar in.

Think of it as a sheet on a close line on a windy day and you are holding the bottom of it. If you move your arms out, the bottom of the sheet moves out and the sheet will be more efficient and offer less pull as the wind blows across it with more ease. If you pull the sheet in, the sheet becomes less efficient and holds more wind in its billow and creates more power / resistance.

While you aren't creating billow per se, the sheeting works the same with a depowerable. You are changing the angle of attack of the kite to make it more efficient and speedy (less lifty) or less efficient and more lifty.

PHREERIDER - 20-5-2008 at 04:23 PM

it is a sailing term-generally when flying a reach or broad reach (across the wind) the main sail can be" let out" to spill wind and lessens the power and speed generated. so letting the bar out allows more wind to spill from the rig(actually changing AoA). that is the static look of the sheet, the dynamic picture of the boat, board, buggy or whatever (or just running around)you could also "fall of the wind" which heading more downwind direction. both are ways of controlling power, speed and course of travel. static it's all about the rig catching air, the dynamic picture all must be considered for direction and rate of travel, this also includes any vertical component

Bladerunner - 20-5-2008 at 04:45 PM

I hear you !
You have the term sheeting right.
I'm getting good and comfortable " sheeting my kite " but I'm wishing someone would go through what strap setting works best for what winds. I'm finding that with my 13 I have to have it just under fully DEpowered to fly well in LOW wind ? When it's windy I'm afraid to trim out ??? With my Pulse it doesn't seem to fly well unless the strap is about 50/50 low wind or high ???

When it comes to sheeting the kite by the bar here is what I find :duh:

Depower is a subjective term ? When the kite is in the power zone sheeting out (bar out or depowering ) actually speeds the kite up and that ='s a boost in power. Only at the edge does the depower apply ?

Same with Power. Sheeting in ( powering up bar in ) when in the power zone has the opposite effect. It's like applying brakes it slows the kite right down and reduces the speed / pull. At the edge of the window pulling in makes power.

It is easier to steer with a bit of a pull in on the bar and better to generate power pushing it out a bit as you pass through the power zone. Try not to be swinging the bar from one end to the other all the time. Like everything else it's better to move small and smooth !

Now can someone explain the logic for setting my trim strap :puzzled:

PHREERIDER - 20-5-2008 at 05:14 PM

trim strap is a limiter of the system. Stability in the neutral zone is where the trim is set for the specific conditions for the session. you want neutral to really be neutral without surprises. but on the fly trim can help as wind picks up say further down the ride or furher out on the water. like setting the idle on an engine a known return point of power and speed. within the power zone it may limit you top or bottom end. that is the part that is "trimmed" the top or the bottom(of the power range). it want change alot just the limits.

DenisLaMenace - 20-5-2008 at 05:23 PM

Quote:
Originally posted by Bladerunner
I hear you !
You have the term sheeting right.
I'm getting good and comfortable " sheeting my kite " but I'm wishing someone would go through what strap setting works best for what winds. I'm finding that with my 13 I have to have it just under fully DEpowered to fly well in LOW wind ? When it's windy I'm afraid to trim out ??? With my Pulse it doesn't seem to fly well unless the strap is about 50/50 low wind or high ???

When it comes to sheeting the kite by the bar here is what I find :duh:

Depower is a subjective term ? When the kite is in the power zone sheeting out (bar out or depowering ) actually speeds the kite up and that ='s a boost in power. Only at the edge does the depower apply ?

Same with Power. Sheeting in ( powering up bar in ) when in the power zone has the opposite effect. It's like applying brakes it slows the kite right down and reduces the speed / pull. At the edge of the window pulling in makes power.

It is easier to steer with a bit of a pull in on the bar and better to generate power pushing it out a bit as you pass through the power zone. Try not to be swinging the bar from one end to the other all the time. Like everything else it's better to move small and smooth !

Now can someone explain the logic for setting my trim strap :puzzled:


good explanation !

I find strange your concerns about the straps on the P3, unless my english is not good enough and I miss something ???

with all my FS when the wind is low, I just pull the strap a little bit below fully powered

if it does not do that, then I dont know, and I would answer the same anyone says on foilzone: have you done the mixer test :frog:

Bladerunner - 21-5-2008 at 08:30 AM

What you say makes sense and is what I was taught.
What I'm finding is that if I trim for stability in the neutral zone it is almost always 50/50 on the Pulse . I have only had the 13 out twice. 1st day wind was strong and gusty for such a big kite. Plenty of depower on the strap made sense. Last weekend the wind was very low. It seemed like if I set it to sit nice at neutral it responded poorly and didn't generate enough power in the power zone. With lots of depower I could really speed it up through the zone and it generally responded better?

So as a general rule .... Trim the kite so it just sits nice and stable with the bar out ??? Does that make sense ??



Quote:
Originally posted by goldendmd
trim strap is a limiter of the system. Stability in the neutral zone is where the trim is set for the specific conditions for the session. you want neutral to really be neutral without surprises. but on the fly trim can help as wind picks up say further down the ride or furher out on the water. like setting the idle on an engine a known return point of power and speed. within the power zone it may limit you top or bottom end. that is the part that is "trimmed" the top or the bottom(of the power range). it want change alot just the limits.

PHREERIDER - 21-5-2008 at 10:07 AM

really depends where you like the bar. i like to trim with the bar all the way in "unhooked scenario" so there is some to sheet out, when hooked then check it,you still should have good idle with the bar out a little . in light wind the sweet spot for usable power is small so even huge adjustments may be ineffective and now movement of the kite becomes the trim feedback component. when i fly in light wind everything is wicked all the way out and window position becomes more important. feedback through the bar and power tension really should be felt out every time. eventually you know how the rig works best by the feel... too mushy, too soft, slow let out the trim a little(catching more air)....too snatchy, too flinty trim in (lessen the air through) bar position is fliers choice.
and if trimmed when the bar is all the way out, when you pull in the kite could be over sheeted and that chokes the kite. (not letting enough air move through the kite and essentially above it)

awindofchange - 21-5-2008 at 11:37 AM

I think some of your confusion (bladerunner) is in the winds that you are flying in. Along with controlling the power of the kite with the trim adjuster and the sheet, you can also control some of the power with the kite as it flies through the air. Example - when the kite is parked it is producing very little power, when the kite is ripping through the window it is creating a ton of power. This power burst as the kite is moving is caused by what is called "apparent wind" meaning that the faster the kite flies, the more power the kite produces because it is flying at speed creating it's own wind vortex around the kite as it moves.

Now, applying this knowledge to your trim strap you can see that by pulling your trim strap in (shortening it to its shortest length) you will allow the kite to fly through the window faster instead of stalling - therefore the kite will produce more power in the light wind conditions COMPARED to letting the trim strap out and causing the kite to stall and create nearly zero power.

Same scenario in stronger winds will produce totally different results. If the wind is strong enough then the kite is much less prone to stall out and letting the strap out will produce more power as the kite catches more wind in the sail and pulling the trim strap in will allow the kite to dump the excess wind off the sail and the kite will produce less power. With the stronger winds and the strap out the kite will pull like a truck because the wind will create more power than you would get from the speed of the kite - unlike the light wind conditions. For maximum power you want to find the optimum setting where the kite still has good controllable speed while still producing maximum power without stalling or slowing the kite to much.

Basically, if you have enough wind to fly you will want to start with your trim strap fairly short (in quite a bit) then work the kite and ride. If you find that you have to work the kite a ton and you are not going as good as you want, let the strap out a bit and try again. If the wind picks up and you start getting blown over then pull the strap in and spill the power.

All of this works in conjunction with your control bar. Think of it as the trim adjuster is an overall power adjustment and the bar is instant fine tuning. :)

Hope that helps.

acampbell - 21-5-2008 at 11:42 AM

In light winds, a de-power kite will seem to react "bass-ackwards". Sheeting in will stall the kite and reduce power; sheeting out reduces angle of attack and in this case speeds up the kite so it flies and generates some power.

Now, sit in the buggy or get on a board and get some velocity and the kite behaves "normally" in its own apparent wind.
With the Montana 3, in light wind not only will I fully pull the de-power strap all the way in (max de-power) just to get the kite flying, but I may grab the center strap and give a good tug as well.

kiteNH - 21-5-2008 at 12:18 PM

Thanks to everyone for this great information. Its very helpful for someone with limited depower experience. I have noticed the backwards control in light winds, but I don't think I've paid enough attention to the trimming of the kite. I've left the trim alone unless overpowered and then trimmed in. It sounds like in lighter winds I might actually want the kite trimmed some so that I can keep it moving and not stall it. :thumbup:

Bladerunner - 21-5-2008 at 01:21 PM

LOTS of great advice. Thanks everyone !

acampbell - 21-5-2008 at 01:32 PM

FWIW Trivia: As Goldendmd says, "sheet" is a sailing term. Specifically, a sheet on a sailboat is the line that runs from the end of the sail boom to a block (pully), usually on the deck, and is the primary means of controlling the position of the boom and its angle relative to the wind. Pull the sheet in and you are "sheeting in" and increasing AoA and power, to a point (stall/ luff). Sheet out and you reduce AoA, spill wind and power until the sail flags.